Tim Peake and space station crew mates return to Earth

The European Space Agency’s Rosetta spacecraft closed in Thursday for a deliberate crash landing on the surface of comet 67P/Churyumov-Gerasimenko on Friday, a slow-motion kamikaze plunge to bring the enormously successful mission to an end after more than two years of unprecedented close-range observations.

Scientists examining imagery from Europe’s Rosetta spacecraft have logged numerous changes to the face of comet 67P/Churyumov-Gerasimenko, from collapsing cliffs to a growing crack through the comet’s neck that could foretell the eventual unraveling of the city-sized icy world.

By pinning down, for the first time, the three-dimensional motions of individual stars in the nearby Sculptor dwarf galaxy, astronomers have shed new light on the distribution of invisible dark matter that pervades the galaxy.